我目前实现了从服务器（url）解析 json。但我找不到从 sdcard (/Download/example.json) 解析 json 的方法。有人可以帮我解决这个问题/更改此代码吗？
我为此使用了 asyncTask。示例教程或示例代码更受欢迎。（对不起我的英语不好。）
public class Main extends Activity {
private TextView shopsDisplay;
private static String searchURL = "http://example.com/sample.json";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.baby);
//reference throughout class
shopsDisplay = (TextView)findViewById(R.id.tweet_txt);
new GetShops().execute(searchURL);
}
private class GetShops extends AsyncTask<String, Void, String> {
/*
* Carry out fetching task in background
* - receives search URL via execute method
*/
@Override
protected String doInBackground(String... shopsURL) {
//start building result which will be json string
StringBuilder shopsFeedBuilder = new StringBuilder();
//should only be one URL, receives array
for (String searchURL : shopsURL) {
HttpClient shopsClient = new DefaultHttpClient();
try {
//pass search URL string to fetch
HttpGet shopsGet = new HttpGet(searchURL);
//execute request
HttpResponse shopsResponse = shopsClient.execute(shopsGet);
//check status, only proceed if ok
StatusLine searchStatus = shopsResponse.getStatusLine();
if (searchStatus.getStatusCode() == 200) {
//get the response
HttpEntity shopsEntity = shopsResponse.getEntity();
InputStream shopsContent = shopsEntity.getContent();
//process the results
InputStreamReader shopsInput = new InputStreamReader(shopsContent);
BufferedReader shopsReader = new BufferedReader(shopsInput);
String lineIn;
while ((lineIn = shopsReader.readLine()) != null) {
shopsFeedBuilder.append(lineIn);
}
}
else
shopsDisplay.setText("Whoops - something went wrong!");
}
catch(Exception e){
shopsDisplay.setText("Whoops - something went wrong!");
e.printStackTrace();
}
}
//return result string
return shopsFeedBuilder.toString();
}
/*
* Process result of search query
* - this receives JSON string representing shops with search term included
*/
protected void onPostExecute(String result) {
//start preparing result string for display
StringBuilder shopsResultBuilder = new StringBuilder();
try {
//get JSONObject from result
JSONObject resultObject = new JSONObject(result);
//get JSONArray contained within the JSONObject retrieved - "results"
JSONArray shopsArray = resultObject.getJSONArray("shops");
//loop through each item in the shops array
for (int t=0; t<shopsArray.length(); t++) {
//each item is a JSONObject
JSONObject shopsObject = shopsArray.getJSONObject(t);
//for if condition
String id = (String) shopsObject.get("id");
//get the name and description for each shops
if (id.equals("550")){
shopsResultBuilder.append(shopsObject.getString("name")+": ");
shopsResultBuilder.append(shopsObject.get("description")+"\n\n");
}
}
}
catch (Exception e) {
shopsDisplay.setText("Whoops - something went wrong!");
e.printStackTrace();
}
//check result exists
if(shopsResultBuilder.length()>0)
shopsDisplay.setText(shopsResultBuilder.toString());
else
shopsDisplay.setText("Sorry - no shops found for your search!");
}
}
}